1. Technical Field
The present invention relates to an image recording apparatus.
2. Related Art
Conventionally, the corona transfer format has been used as the transfer mechanism in high-speed continuous paper printers. However, the adoption of the transfer roller format is preferable as a measure to counter transfer defects of stepped media and transfer defects resulting from the use of coarse paper/thin paper and paper wrinkles at the time of heavy continuous printing.
The transfer roller format is a technique that is usually adopted in cut paper printers, but there are several technical issues when the transfer roller format is adopted in high-speed continuous paper printers. Important among them is the stability of contact between the paper, the photoconductor drum, and the transfer roller.
Conventionally, in printers adopting the transfer roller format (cut paper), the transfer roller causes the paper to be pressed against and contact the photoconductor drum, but when continuous paper is used rather than cut paper, tension is imparted to the continuous paper in order to convey the paper before and after transfer.
For this reason, it becomes necessary for the transfer roller to cause the paper to be pressed against and contact the drum with a pressure overcoming the tension of the paper. But with continuous paper, it becomes difficult to cause the drum and the paper to appropriately contact each other because the transfer pressure becomes extremely large, and the deformation amount of the transfer roller also becomes larger.
A width of contact between the drum and the paper can be stably obtained by disposing a guide member in order to obtain stable contact between the continuous paper and the drum and regulating the conveyance position of the continuous paper. Thus, it becomes unnecessary for the transfer roller to include the function of causing the paper to be pressed against and contact the drum, so that the function of transfer charge supply can become the main function of the transfer roller. For this reason, the selection of the material for the transfer roller becomes freed from the restrictions of physical characteristics, and the performance of transfer charge supply can be pursued, such that a higher quality image can be obtained.
Conventionally, because the transfer roller nip width and the paper contact width are substantially the same, the transfer application region becomes substantially equivalent to the nip width, but when a guide roller is used, it is necessary to set the optimum condition because the paper contact width and the transfer nip width are different.